The present disclosure relates generally to the field of automated maintenance (including non-destructive inspection) of wind turbine blades, and more particularly to an automated end effector-carrying apparatus that is coupled to and travels along a wind turbine blade while performing a maintenance function. As used herein, the term “maintenance” includes, but is not limited to, operations such as nondestructive inspection, drilling, scarfing, grinding (e.g., to remove bonded or bolted components), fastening, applique application, ply mapping, cleaning, marking and painting.
A typical wind turbine has a multiplicity of blades extending radially outward from a central hub, to which the roots of the blades are attached. The hub is rotatably coupled to a nacelle that is supported at a height above ground by a tower. The blades are configured to generate aerodynamic forces that cause the wind turbine to rotate in response to wind impinging on the blade surfaces. The nacelle houses an electric generator which is operatively coupled to the hub. The electric generator is configured to generate electrical power as the hub rotates.
Wind turbine blades are typically made of laminated fiber-reinforced plastic material and designed so that the wind energy is converted into rotational motion efficiently. Blade efficiency is generally dependent upon blade shape and surface smoothness. However, during operation the wind turbine blades may be exposed to debris that has the potential to reduce wind turbine efficiency or may be subjected to damage that has the potential to adversely affect structural integrity. Thus, it is common practice to visually inspect the exterior of each blade to identify potential structural anomalies or perform some other maintenance operation on the exterior, such as cleaning.
It is known to manually inspect and clean wind turbine blades by hoisting a person to a position adjacent to each blade via suspension from the tower, the hub, or a proximately located crane. However, manual blade inspection and cleaning can be time-consuming and difficult operations. To mitigate the drawbacks of manual inspection and cleaning, various solutions involving an apparatus configured to travel in a spanwise direction along the length of a wind turbine blade have been proposed. However, there is ample scope for improvements in the state of this art.